Per Bylund writes for Observer.com:
Nearly 80 years ago — during the height of the Great Depression — economist Simon Kuznets envisioned a system capable of measuring productivity and economic activity. In a report to Congress, Kuznets proposed charting all economic production with a single measurement that would decrease when the economy struggled and increase when it thrived. He called it gross domestic product, or GDP.
Nations throughout the world embraced GDP as the standard for measuring economic activity; Kuznets eventually won the Nobel Prize for his creation. The popularity of GDP belies its effectiveness, however, as the measure systematically under-reports the significance of production.